Typical fuel cell arrangements include multiple fuel cells placed together in a cell stack assembly (CSA). Each fuel cell generally includes an anode, a cathode, and a membrane between the anode and the cathode. A cathode reactant, such as oxygen, and an anode reactant, such as hydrogen, are used in an electro-chemical reaction at the membrane to produce electrical energy.
CSA durability can be limited by a variety of decay mechanisms or factors. For example, voltage cycling may cause performance decay over time. Local membrane humidity cycling may cause the membrane to wear out. Both of these types of cycling may occur in response to changes in load or power demand. Another source of CSA decay is an elevated operating temperature. Higher operating temperatures tend to be associated with higher decay rates in CSA performance. A number of approaches have been taken to mitigate CSA decay caused by elevated operating temperatures.